为了降低刀具的磨损，延长刀具的使用寿命，以兰州地铁工程施工案例为背景，对土压平衡盾构在砂卵石地层中掘进刀具磨损的问题进行了跟踪研究。通过理论计算与工程实际对比分析得出刀具的磨损规律，在刀盘设计和刀具组合等研究成果的基础上，对渣土改良、盾构掘进参数、盾构姿态和一般欠土压模式掘进等控制措施进行了系统的研究和实践，成功地延长了刀具使用寿命，减少了刀具更换的次数，加快了工程进度并降低了工程成本；同时，解决了土压平衡盾构在砂卵石地层掘进刀盘被卡、地面沉降控制等技术难题。

The wear of cutting tools of EPB shield boring in sandy cobble stratum in Lanzhou is studied, so as to reduce wear of cutting tools and increase the service life of cutting tools.The wear rules of cutting tools are obtained by making comparison between theoretical calculation results and actual practice. Study is made on technologies, i.e. ground conditioning, boring parameter optimization, shield altitude control and shield boring under inadequate soil stress, on basis of study results of cutterhead design and cutting tool arrangement. The service life of cutting tool has been increased; the cutting tool replacing times have been reduced; the construction schedule has been shortened; and the construction cost has been reduced.